Income Taxes - Net Deferred Income Tax Liability (Details) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Other non-current assets	$ 18.3	$ 18.1
Deferred tax liabilities	41.3	40.5
Net Deferred Income Tax Liability	$ 23.0	$ 22.4

Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences, with jurisdictional netting and classified as noncurrent.

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